1. Field of the Invention
The invention relates to a sleeve valve device for fluid flow between a hydrocarbon reservoir and a well in the hydrocarbon reservoir, wherein the well in the reservoir area comprises a casing, where the sleeve valve has an elongate, cylindrical shape and is mounted inside the casing or integrated in a portion of the casing and comprises a fixed outer sleeve and a rotatable inner sleeve which can be rotated by means of an actuator or a tool in order to bring apertures in the outer sleeve and the inner sleeve into and out of correspondence with each other, for adjustment of the fluid flow through the apertures.
The invention also relates to a method for assembly of the sleeve valve device, where the outer sleeve and the inner sleeve are produced separately.
2. Description of the Prior Art
For the recovery of hydrocarbons from-hydrocarbon reservoirs, wells are drilled from the seabed or the surface of the earth down to the reservoir which is under pressure. The wells are lined with casing to prevent them from collapsing. The casing is perforated in the reservoir area, thus enabling hydrocarbons to flow into the well. In order to lead the hydrocarbon flow out of the reservoir area, a production tubing is placed inside the casing. This production tubing extends from the seabed or the surface of the earth down to a production packer which is mounted between the tubing and the internal wall of the casing on the edge of or outside the reservoir area, and whose task is to prevent hydrocarbons from flowing up into the well on the outside of the tubing.
The well may extend for a great distance through the reservoir, for example 2000 metres. A hydrocarbon reservoir normally contains both oil, gas and water. The production conditions, i.e. primarily the amount of oil, gas and water and the pressure in the reservoir, usually vary along the well, and are altered in the course of the production period. The flow into the well at the various locations in the reservoir may be an almost pure flow of oil, gas or water, or a mixture of two or all three of these components.
In order to be able to maintain the pressure in the reservoir, and thereby maintain the flow into the well, it is always desirable to cut off the flow of water into the well. Whether it is desirable to cut off the influx of gas and flows containing a mixture of oil, gas and water depends on the capacity and type of processing equipment which process the well flow after it has emerged from the well. In some places it may be desirable to have a partial shut-off of the flow.
In order to maintain the pressure in the reservoir, in some places water or gas injection is employed, in which case it may be desirable to have the capability of controlling the influx into the reservoir along the well.
In order to regulate the flow to or from a well, sleeve valves may be employed, which can be mounted integrated in a portion of the casing, or which can be placed inside the casing. In order to be able to regulate the flow to or from the well at different places in the reservoir, sleeve valves are located at suitable intervals in the well. The sleeve valves comprise an external sleeve and an internal sleeve, both of which are equipped with apertures. The external sleeve is fixed, while the internal sleeve is movable in order to bring apertures in the two sleeves into and out of correspondence with each other for opening or closing the flow through the sleeve valve.
The sleeve valves have reciprocally movable surfaces facing each other, which surfaces in some of the positions of the sleeve valves are exposed to fluids in the well. Components found in these fluids have a tendency to be deposited on exposed surfaces, with the result that the sleeve valves may become jammed or cemented together by deposits.
A second problem associated with valves in hydrocarbon wells is sand, which becomes jammed in the valves and causes wear on movable surfaces.
A third problem is that the valves may be exposed to substantial pressure differences between the inside and the outside. These pressure differences may expand or compress the valves, thus influencing the valves' ability to block off the flow.
Problems of the above kind are known within other fields, and are often solved by flexible gaskets of a non-metallic material. In an oil well, however, the temperature may be 100° C., the pressure 200 bar or more, and there may be components which corrode the seal materials. Experience shows that no known seal materials can withstand such conditions over several years, and it is therefore desirable to find other constructive solutions to the above-mentioned problems.
U.S. Pat. No. 6,044,908 describes a sliding sleeve valve for controlling fluid flow between a well annulus and a string of well conduit, which valve comprises a slideable sleeve disposed coaxially within an outer housing, the valve being provided with a primary seal member carried by the housing for sealing engagement with the housing. The primary seal member in a relaxed condition comprises an annular, monolithic body with a first, radially outwardly facing, annularly extending seal surface, and a second, radially inwardly facing, annularly extending seal surface, the second seal surface having at least one annularly extending, radially inwardly projecting rib, the rib having a radially innermost convex portion when viewed in transverse cross-section, annularly extending reliefs being formed on axially opposite sides of the rib, the seal member being made of a substantially non-elastomeric material that has sufficient memory to provide an interference seal between the seal member and the housing, and the seal member and the sleeve.
U.S. Pat. No. 5,080,325 describes coating of corrosion-prone parts in valve devices with corrosion-proof metal alloys.
U.S. Pat. No. 5,285,850 describes a well completion system which is connected to coiled tubing, with a sliding sleeve valve for controlling a flow of production fluid into the tubing string.